Cell culture on artificial capillaries has been shown to provide a pericellular microenvironment more closely resembling the in vivo state than that provided by monolayer culture. Cell types inoculated into the artificial capillary bed form solid tissue masses within a few weeks and behave in ways that appear to simulate their in vivo behavior. These properties have made possible the applications for continuous virus production, culture of human bone marrow, and production of human hormones.